1. Field of the Invention
The invention relates to a driving device, and more particularly to a driving device for driving a laser diode.
2. Description of the Related Art
Laser diodes (LDs), due to their small size, low cost and ease of use, are widely employed in a variety of fields, such as optical storage, light reading, light communication, and distance measurement. Driving devices are required for driving LDs. Driving device requirements differ by purpose.
FIG. 1 is a chart showing the driving current of the LD relative to the output power of LD at different temperatures. When the driving current exceeds a threshold current Ith, a laser beam emitted by the LD is an effective laser beam. Additionally, temperature profoundly affects LD output power. At the same current, when temperature is higher, output power is lower.
In the majority of LD applications, such as CDs, DVDs, long distance, middle distance, or short distance measurements, LDs are required for stably emitting a stably laser beam. Thus, LDs require suitable driving devices. A suitable driving device provides a driving current sufficient for the LD to produce an effective laser beam.